Light-absorbing flange lenses

ABSTRACT

Light-absorbing flange lenses that may be used in the lens stacks of compact lens systems. In a light-absorbing flange lens, the effective area of the lens is composed of a transparent optical material, and at least a portion of the flange of the lens is composed of an optical material that absorbs at least a portion of the light that enters the flange. Using light-absorbing flange lenses may allow the lens barrel to be eliminated from the lens system, thus reducing the X-Y dimensions of the lens system when compared to conventional compact lens systems that include a lens stack enclosed in a lens barrel. In addition, using a light-absorbing material in the flanges of the light-absorbing flange lenses may reduce or eliminate optical aberrations such as lens flare, haze, and ghosting in images.

PRIORITY INFORMATION

This application is a continuation of U.S. patent application Ser. No.16/705,118, filed Dec. 5, 2019, which claims benefit of priority of U.S.Provisional Application Ser. No. 62/776,973 entitled “LIGHT-ABSORBINGFLANGE LENSES” filed Dec. 7, 2018, the content of which are incorporatedby reference herein in their entirety.

BACKGROUND Description of the Related Art

The advent of small, mobile multipurpose devices such as smartphones andtablet or pad devices has resulted in a need for high-resolution, smallform factor cameras for integration in the devices. However, due tolimitations of conventional camera technology, conventional smallcameras used in such devices tend to capture images at lower resolutionsand/or with lower image quality than can be achieved with larger, higherquality cameras. Achieving higher resolution with small package sizecameras generally requires use of a photosensor with small pixel sizeand a good, compact imaging lens system. Advances in technology haveachieved reduction of the pixel size in photosensors. However, asphotosensors become more compact and powerful, demand for compactimaging lens system with improved imaging quality performance hasincreased.

SUMMARY OF EMBODIMENTS

Embodiments of the present disclosure may provide a camera in a smallpackage size, referred to as a small format factor camera. Embodimentsof a compact lens system are described that may include one or morerefractive lens elements, referred to as a lens stack. Embodiments oflight-absorbing flange lenses are described that may be used in the lensstack instead of conventional unibody lens elements in which theeffective area and flange of the lens elements are composed of the sametransparent optical material. In a light-absorbing flange lens, theeffective area is composed of a transparent optical material; however,at least a portion of the flange of the lens is composed of an opticallight-absorbing material that absorbs at least a portion of the lightthat enters the flange. Using light-absorbing flange lenses allows thelens barrel to be reduced or eliminated from the lens system. This has asignificant impact on the X-Y size of the camera by reducing the size ofthe camera in the X-Y dimensions. This may allow the X-Y dimensions ofthe camera to be reduced when compared to a similar camera in which thelens system includes unibody lenses in a lens stack enclosed by anopaque lens barrel.

In addition, using a light-absorbing material in the flanges of thelight-absorbing flange lenses may reduce or eliminate opticalaberrations such as lens flare, haze, and ghosting in images capturedwith the camera because the portion of the light entering through thefront (object side) of a light-absorbing flange lens is absorbed ratherthan being reflected by surfaces of the flange and exiting through theimage side of the lens element as in unibody lens elements.

In some embodiments, the refractive index of the optical light-absorbingmaterial used in the flange of the lens element may be higher than therefractive index of the optical transparent material used in theeffective area of the lens element. This may help to further reduceflare or other aberrations.

Embodiments of the light-absorbing flange lenses may be used in infraredcamera applications as well as in visible light camera applications. Insome embodiments, the light-absorbing material in the flange of alight-absorbing flange lens is an optical material that absorbs bothvisible light and infrared (IR) light. However, in some embodiments, thelight-absorbing material in the flange of a light-absorbing flange lensis an optical material that absorbs light in the visible portion of thespectrum while transmitting at least a portion of the light in the IRportion of the spectrum. This may allow mechanical features of thecamera/lens to be detected using IR light, for example allowing thelenses to be inspected using IR light during or after manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a camera lens system, according to some embodiments.

FIG. 2A is a cross-sectional illustration of an example camera lenssystem that includes refractive lens elements mounted in a lens barrel,according to some embodiments.

FIG. 2B illustrates the flange and effective portions of a lens element,according to some embodiments.

FIG. 3 illustrates flare caused by the flange of a unibody lens element,according to some embodiments.

FIGS. 4A through 4C illustrate flanges of lens elements that are atleast partially composed of an optical light-absorbing material toreduce or eliminate optical aberrations such as flare, according to someembodiments.

FIG. 5 is a cross-sectional illustration of another example camera lenssystem that includes refractive lens elements mounted in a lens barrel,according to some embodiments.

FIG. 6 is a cross-sectional illustration of an example camera lenssystem that includes refractive lens elements in which the flanges areat least partially composed of an optical light-absorbing material thatallows the lens barrel to be reduced or eliminated, thus reducing thediameter of the lens system, according to some embodiments.

FIG. 7 is a cross-sectional illustration of another example camera lenssystem that includes refractive lens elements in which the flanges areat least partially composed of an optical light-absorbing material thatallows the lens barrel to be reduced or eliminated, thus reducing thediameter of the lens system, according to some embodiments.

FIG. 8 illustrates a flange of a lens element that is at least partiallycomposed of a material that absorbs visible light and IR light,according to some embodiments.

FIG. 9 illustrates a flange of a lens element that is at least partiallycomposed of a material that absorbs visible light and transmits infrared(IR) light, according to some embodiments.

FIG. 10 illustrates an injection molding process for forming alight-absorbing flange lens in which the flange is formed before theeffective (center) area of the lens element, according to someembodiments.

FIG. 11A illustrates an injection molding process for forming alight-absorbing flange lens in which the effective (center) area of thelens element is formed before the flange, according to some embodiments.

FIG. 11B illustrates an injection molding process for forming alight-absorbing flange lens in which the effective (center) area of thelens element and part of the flange formed of a transparent materialbefore a light-absorbing part of the flange is formed, according to someembodiments.

FIG. 12 is a high-level flowchart of a method for capturing images usinga camera that includes a lens stack in which the flanges of one or moreof the lens elements are at least partially composed of alight-absorbing material as illustrated in FIGS. 4A and 4B, according tosome embodiments.

FIGS. 13A through 13C illustrate example optical systems that includeprisms that fold the optical axis, according to some embodiments.

FIG. 14 illustrates an example prism formed with a light-absorbingholder, according to some embodiments.

FIG. 15 illustrates an example prism with optical power formed with alight-absorbing holder, according to some embodiments.

FIG. 16 illustrates an example prism with optical power formed with alight-absorbing holder that includes a mounting structure, according tosome embodiments.

FIG. 17 illustrates an example prism formed with an alternativelight-absorbing holder, according to some embodiments.

FIG. 18 illustrates an example filter formed with a light-absorbingholder, according to some embodiments.

FIG. 19 illustrates an example computer system that may be used inembodiments.

This specification includes references to “one embodiment” or “anembodiment.” The appearances of the phrases “in one embodiment” or “inan embodiment” do not necessarily refer to the same embodiment.Particular features, structures, or characteristics may be combined inany suitable manner consistent with this disclosure.

“Comprising.” This term is open-ended. As used in the appended claims,this term does not foreclose additional structure or steps. Consider aclaim that recites: “An apparatus comprising one or more processor units. . . ”. Such a claim does not foreclose the apparatus from includingadditional components (e.g., a network interface unit, graphicscircuitry, etc.).

“Configured To.” Various units, circuits, or other components may bedescribed or claimed as “configured to” perform a task or tasks. In suchcontexts, “configured to” is used to connote structure by indicatingthat the units/circuits/components include structure (e.g., circuitry)that performs those task or tasks during operation. As such, theunit/circuit/component can be said to be configured to perform the taskeven when the specified unit/circuit/component is not currentlyoperational (e.g., is not on). The units/circuits/components used withthe “configured to” language include hardware—for example, circuits,memory storing program instructions executable to implement theoperation, etc. Reciting that a unit/circuit/component is “configuredto” perform one or more tasks is expressly intended not to invoke 35U.S.C. § 112, sixth paragraph, for that unit/circuit/component.Additionally, “configured to” can include generic structure (e.g.,generic circuitry) that is manipulated by software and/or firmware(e.g., an FPGA or a general-purpose processor executing software) tooperate in manner that is capable of performing the task(s) at issue.“Configure to” may also include adapting a manufacturing process (e.g.,a semiconductor fabrication facility) to fabricate devices (e.g.,integrated circuits) that are adapted to implement or perform one ormore tasks.

“First,” “Second,” etc. As used herein, these terms are used as labelsfor nouns that they precede, and do not imply any type of ordering(e.g., spatial, temporal, logical, etc.). For example, a buffer circuitmay be described herein as performing write operations for “first” and“second” values. The terms “first” and “second” do not necessarily implythat the first value must be written before the second value.

“Based On.” As used herein, this term is used to describe one or morefactors that affect a determination. This term does not forecloseadditional factors that may affect a determination. That is, adetermination may be solely based on those factors or based, at least inpart, on those factors. Consider the phrase “determine A based on B.”While in this case, B is a factor that affects the determination of A,such a phrase does not foreclose the determination of A from also beingbased on C. In other instances, A may be determined based solely on B.

DETAILED DESCRIPTION

Embodiments of a compact lens system, which may also be referred to as alens system, are described that may include one or more refractive lenselements, referred to as a lens stack. Embodiments of the compact lenssystem may be used in cameras with a small package size, referred to assmall format factor cameras. Embodiments of small format factor camerasare described that include, but are not limited to, a photosensor andembodiments of the compact lens system.

Conventionally, lens systems for small form factor cameras include alens stack composed of two or more refractive lens elements. Each lenselement in the lens stack may include an effective optical area and aflange area, and may be formed of a transparent optical plastic or glassmaterial. For example, the lens elements may be injection-molded opticalplastic. While one or more of the lens elements may be formed oftransparent optical materials with different optical characteristics(e.g., Abbe number and refractive index (n)), the flange and effectiveoptical area of each lens element are conventionally formed of the sameoptical material. These lens elements may be referred to as “unibody”lenses as the flange and effective optical area are both formed of thesame optical material, for example via an injection molding process.Using unibody lenses requires the lens system to include a lens barrelcomposed of an opaque material to cover the lens stack.

Problems with these conventional lens systems include, but are notlimited to:

-   -   The lens barrel increases the X-Y size of the lens system.        Minimizing the X-Y size of the lens system is desirable for        certain applications of small form factor devices. For example,        in many small form factor devices such as smartphones and tablet        or pad devices, a front-facing camera may be mounted in the        bezel, between the screen and the edge of the device. Thus, the        X-Y dimensions of the lens system of a front-facing camera limit        the size of the bezel, as the bezel has to be wide enough to        accommodate at least the front portion of the lens system.    -   The flanges of the unibody lenses may cause optical aberrations        such as lens flare, haze, and ghosting in images captured with        the camera. This is because a portion of the light entering        through the front (object side) of a unibody lens element may be        reflected into the flange, and a portion of that light may be        reflected by surfaces of the flange and exit through the image        side of the lens element.

Embodiments of light-absorbing flange lenses are described that may beused in a lens stack instead of conventional unibody lens elements. In alight-absorbing flange lens, the effective area is composed of atransparent optical material; however, the flange of the lens is atleast partially composed of a material that absorbs at least a portionof the light that enters the flange. Using light-absorbing flange lensesallows the lens barrel to be eliminated from the lens system. This has asignificant impact on the X-Y size of the camera by reducing the size ofthe camera in the X-Y dimensions. This may allow the X-Y dimensions ofthe camera to be reduced when compared to a similar camera in which thelens system includes unibody lenses in a lens stack enclosed by anopaque lens barrel. For example, in many small form factor devices suchas smartphones and tablet or pad devices, a front-facing camera may bemounted in the bezel, between the screen and the edge of the device.Reducing the X-Y dimensions of the lens system of a front-facing cameraby eliminating the lens barrel may allow a narrower bezel to be used onthe device than would be required by a conventional camera module thatincludes a lens barrel.

In addition, using a light-absorbing material in the flanges of thelenses may reduce or eliminate optical aberrations such as lens flare,haze, and ghosting in images captured with the camera because theportion of the light entering through the front (object side) of alight-absorbing flange lens is absorbed rather than being reflected bysurfaces of the flange and exiting through the image side of the lenselement as in unibody lens elements.

Embodiments of a small format factor camera with a lens system thatincludes light-absorbing flange lenses in the lens stack as describedherein may be implemented in a small package size while still capturingsharp, high-resolution images, making embodiments of the camera suitablefor use in small and/or mobile multipurpose devices such as cell phones,smartphones, pad or tablet computing devices, laptop, netbook, notebook,subnotebook, and ultrabook computers, and so on. However, note thataspects of the camera (e.g., the lens system and photosensor) may bescaled up or down to provide cameras with larger or smaller packagesizes. In addition, embodiments of the camera system may be implementedas stand-alone digital cameras. In addition to still (single framecapture) camera applications, embodiments of the camera system may beadapted for use in video camera applications. In addition to visiblelight camera applications, embodiments of the light-absorbing flangelenses may be used in infrared camera applications. In some embodiments,a camera as described herein may be included in a device along with oneor more other cameras such as a wider-field small format camera or atelephoto or narrow angle small format camera, which would for exampleallow the user to select between the different camera formats (e.g.,normal, telephoto or wide-field) when capturing images with the device.In some embodiments, two or more small format cameras as describedherein may be included in a device, for example as front-facing andrear-facing cameras in a mobile device.

FIG. 1 illustrates a camera lens system 100 that may be used in smallformat factor cameras, according to some embodiments. The lens system100 may include a lens stack 110 including one or more refractive lenselements. The lenses in the lens stack 110 may be mounted or affixedinside a lens barrel 160. A photosensor 150 may be located on the imageside of the lens stack 110 when the lens system 100 is attached to asubstrate 190 that holds the photosensor 150. The lens system 100 mayalso include at least one aperture stop (not shown), for example at afirst lens element in the lens stack 110. The lens system 100 may also,but does not necessarily, include an IR filter that may, for example, bemounted or attached at the rear (image side) of the lens barrel 110.

FIG. 2A is a cross-sectional illustration of an example camera lenssystem 200 that includes lens elements mounted in a lens barrel,according to some embodiments. The lens system 200 may include a lensstack that includes two or more lens elements (five lens elements201-205, in this example) with refractive power arranged along anoptical axis in order from an object side to an image side and locatedwithin a lens barrel 260. An aperture stop may be included in the lensstack, for example at the first lens element or between the first andsecond lens elements. The lens system 200 may also, but does notnecessarily, include an IR filter assembly 270 that may be mounted orattached to the rear (image side) of the lens barrel 260.

The lens elements 201-205 in the lens stack as shown in FIG. 2A aregiven by way of example and are not intended to be limiting. Opticalcharacteristics, materials (e.g., plastics or glass), shapes, spacing,and/or sizes of the lens elements may be selected so that light rays arecorrectly refracted through the lens elements in the lens stack to forman image at an image plane on or proximate to a photosensor of a camera.More or fewer lens elements (e.g., four lens elements, six lenselements, etc.) may be used in the lens stack, and one or more of thelens elements in the lens stack may be of different shapes, geometries,sizes, or materials with different optical properties (e.g., refractiveindex or Abbe number). Spacing between the lens elements in the lensstack may be different than shown, and various power orders for the lenselements in the lens stack may be used. For example, in the example fivelens element lens stack of FIG. 2A, the power order, from the first lenselement to the fifth lens element, may be PNNNP, PNPNP, or some otherorder, where P indicates a lens with positive refractive power, and Nrepresents a lens with negative refractive power.

FIG. 2B illustrates the flange and effective portions of an example lenselement 201 in the lens stack shown in FIG. 2A, according to someembodiments. As shown in FIG. 2A, at least one lens element in the lensstack may include an effective optical area and a flange area, and maybe formed of a transparent optical plastic or glass material. Forexample, the lens elements may be injection-molded optical plastic.While one or more of the lens elements may be formed of transparentoptical materials with different optical characteristics (e.g., Abbenumber and refractive index (n)), the flange and effective optical areaof each lens element are conventionally formed of the same opticalmaterial. These lens elements may be referred to as “unibody” lenses asthe flange and effective optical area are both formed of the sameoptical material, for example via an injection molding process.

As previously noted, using unibody lenses as shown in FIGS. 2A and 2Brequires a lens barrel 260 composed of an opaque material to cover thelens stack. However, the lens barrel 260 increases the X-Y size of thelens system. In addition, the flanges of the unibody lenses may causeoptical aberrations such as lens flare, haze, and ghosting in imagescaptured with the camera.

FIG. 3 illustrates aberrations (e.g., flare) caused by the flange of aunibody lens element, according to some embodiments. As shown in FIG. 3, the flange of a unibody lens may cause optical aberrations such aslens flare, haze, and ghosting in images captured with a camera. This isbecause a portion of the light entering through the front (object side)of the effective area of a unibody lens element may be reflected intothe flange, and a portion of that light may be reflected by surfaces ofthe flange and exit through the image side of the lens element.

FIGS. 4A through 4C illustrate flanges of lens elements that are atleast partially composed of an optical light-absorbing material toreduce or eliminate optical aberrations such as flare, according to someembodiments. As shown in FIG. 4A, the effective area of the lens elementis composed of a visible and infrared (IR) light transparent opticalmaterial. The flange of the lens element is at least partially composedof a material that absorbs at least a portion of the light that entersthe flange. In some embodiments, the flange may be composed of amaterial that absorbs light in the visible portion of the spectrum andin the IR portion of the spectrum. However, in some embodiments, theflange may be composed of a material that absorbs light in the visibleportion of the spectrum while transmitting at least a portion of thelight in the IR portion of the spectrum. This may allow mechanicalfeatures of the camera/lens to be detected using IR light, for exampleallowing the lenses to be inspected using IR light during or aftermanufacture. As shown in FIG. 4B, using a material that absorbs at leasta portion of light in the flange of the lens element may reduce oreliminate optical aberrations such as flare. As shown in FIG. 4B, insome embodiments, the refractive index n′ of the light-absorbingmaterial used in the flange of the lens element may be higher than therefractive index n of the optical transparent material used in theeffective area of the lens element. This may help to further improve thereduction of flare or other aberrations. FIGS. 10 and 11A show examplemethods for manufacturing light-absorbing lens elements as illustratedin FIGS. 4A and 4B

FIG. 4C shows an example in which the effective area of the lens elementand a first (e.g., inner) part of the flange are composed of a visibleand infrared (IR) light transparent optical material, and a second(e.g., outer) part of the flange is composed of a material that absorbsat least a portion of the light that enters the flange. In someembodiments, the light-absorbing material absorbs light in the visibleportion of the spectrum and in the IR portion of the spectrum. However,in some embodiments, the light-absorbing material absorbs light in thevisible portion of the spectrum while transmitting at least a portion ofthe light in the IR portion of the spectrum. As shown in FIG. 4C, usingthe light-absorbing material in the flange may reduce or eliminateoptical aberrations such as flare. As shown in FIG. 4C, in someembodiments, the refractive index n′ of the light-absorbing materialused in the flange of the lens element may be greater than or equal tothe refractive index n of the optical transparent material used in theeffective area of the lens element. FIG. 11B shows an example method formanufacturing a light-absorbing lens element as illustrated in FIG. 4C.

In some embodiments, a light-absorbing flange lens may be composed oftwo different plastic materials, with a transparent plastic materialused for the effective area of the lens element and a light-absorbingmaterial that absorbs at least a portion of light used in at least aportion of the flange. In some embodiments, the light-absorbing flangelens may be formed using an injection molding process. In someembodiments, the light-absorbing flange lens may be formed using aninjection molding process in which the effective area is formed first,followed by the flange. However, in some embodiments, thelight-absorbing flange lens may be formed using an injection moldingprocess in which the flange is formed first, followed by the effectivearea.

Note that, in some embodiments, the entire flange may be formed of thelight-absorbing material. However, in some embodiments, a portion butnot all of the flange may be formed of the light-absorbing material.Further note that, in some embodiments of a lens stack, all of the lenselements may be light-absorbing flange lenses as described herein.However, in some embodiments, one or more of the lens elements in thelens stack may be light-absorbing flange lenses as described herein,while one or more others of the lens elements in the lens stack may beunibody lenses.

FIG. 5 is a cross-sectional illustration of another example camera lenssystem that includes refractive lens elements mounted in a lens barrel,according to some embodiments. The lens system 500 may include a lensstack that includes two or more lens elements (four lens elements501-504, in this example) with refractive power arranged along anoptical axis in order from an object side to an image side and locatedwithin a lens barrel 560. An aperture stop may be included in the lensstack, for example at the first lens element or between the first andsecond lens elements. The lens system 500 may also, but does notnecessarily, include an IR filter assembly that may be mounted orattached to the rear (image side) of the lens barrel 560.

The lens elements 501-504 in the lens stack as shown in FIG. 5 are givenby way of example and are not intended to be limiting. Opticalcharacteristics, materials (e.g., plastics or glass), shapes, spacing,and/or sizes of the lens elements may be selected so that light rays arecorrectly refracted through the lens elements in the lens stack to forman image at an image plane on or proximate to a photosensor of a camera.More or fewer lens elements (e.g., four lens elements, six lenselements, etc.) may be used in the lens stack, and one or more of thelens elements in the lens stack may be of different shapes, geometries,sizes, or materials with different optical properties (e.g., refractiveindex or Abbe number). Spacing between the lens elements in the lensstack may be different than shown, and various power orders for the lenselements in the lens stack may be used.

As shown in FIG. 5 , the lens elements in the lens stack may include aneffective optical area and a flange area, and may be formed of atransparent optical plastic or glass material. For example, the lenselements may be injection-molded optical plastic. While one or more ofthe lens elements may be formed of transparent optical materials withdifferent optical characteristics (e.g., Abbe number and refractiveindex (n)), the flange and effective optical area of each lens elementare conventionally formed of the same optical material. These lenselements may be referred to as “unibody” lenses as the flange andeffective optical area are both formed of the same optical material, forexample via an injection molding process.

As previously noted, using unibody lenses as shown in FIG. 5 requires alens barrel 560 composed of an opaque material to cover the lens stack.However, the lens barrel 560 increases the X-Y size of the lens system.In addition, the flanges of the unibody lenses may cause opticalaberrations such as lens flare, haze, and ghosting in images capturedwith the camera.

FIG. 6 is a cross-sectional illustration of an example camera lenssystem 600 that includes refractive lens elements in which the flangesare at least partially composed of a light-absorbing material thatallows the lens barrel to be reduced or eliminated, thus reducing thediameter of the lens system, according to some embodiments. The lenselements 601-604 are similar in shape and optical characteristics to thelens elements 501-504 shown in FIG. 5 . However, at least a portion ofthe flanges of the lens elements 601-604 are composed of a material thatabsorbs at least a portion of the light that enters the flanges. In someembodiments, the flanges may be composed of a material that absorbslight in the visible portion of the spectrum and in the IR portion ofthe spectrum. However, in some embodiments, the flanges may be composedof a material that absorbs light in the visible portion of the spectrumwhile transmitting at least a portion of the light in the IR portion ofthe spectrum. This may allow mechanical features of the camera/lens tobe detected using IR light, for example allowing the lenses to beinspected using IR light during or after manufacture. Using an opticalmaterial that absorbs at least a portion of light for the flange of thelens element may reduce or eliminate optical aberrations such as flare.In addition, using the light-absorbing material for the flanges allowsthe lens barrel to be at least partially eliminated, thus reducing thefront diameter of the lens system 600 when compared to lens system 500.This may allow the X-Y dimensions of the camera to be reduced whencompared to a similar camera in which a lens system 500 as shown in FIG.5 includes unibody lenses in a lens stack enclosed by an opaque lensbarrel 560. For example, in many small form factor devices such assmartphones and tablet or pad devices, a front-facing camera may bemounted in the bezel, between the screen and the edge of the device.Reducing the X-Y dimensions of the lens system of a front-facing cameraby eliminating the lens barrel may allow a narrower bezel to be used onthe device than would be required by a conventional camera module thatincludes a lens barrel as shown in FIG. 5 .

FIG. 7 is a cross-sectional illustration of another example camera lenssystem that includes refractive lens elements in which the flanges areat least partially composed of a light-absorbing material that allowsthe lens barrel to be reduced or eliminated, thus reducing the diameterof the lens system, according to some embodiments. The lens elements701-704 are similar in shape and optical characteristics to the lenselements 501-504 shown in FIG. 5 and the lens elements 601-604 as shownin FIG. 6 . At least a portion of the flanges of the lens elements701-704 are composed of an optical material that absorbs at least aportion of the light that enters the flanges. Using an opticallight-absorbing material that absorbs at least a portion of light forthe flange of the lens element may reduce or eliminate opticalaberrations such as flare. In addition, using the light-absorbingmaterial for the flanges allows the lens barrel to be at least partiallyeliminated, thus reducing the front diameter of the lens system 700 whencompared to lens system 500. In addition, at least the first lenselement 701 and the lens cover have been reconfigured when compared tothe lens system 600 of FIG. 6 to further reduce the front diameter ofthe lens system 700 when compared to lens system 600.

FIG. 8 illustrates a flange of a lens element that is at least partiallycomposed of a material that absorbs visible light and IR light,according to some embodiments. The effective area of the lens element iscomposed of a visible and infrared (IR) light transparent opticalmaterial. The flange of the lens element is at least partially composedof an optical material that absorbs visible light and IR light thatenters the flange. Using a light-absorbing material for the flanges ofthe light-absorbing flange lenses may reduce or eliminate opticalaberrations such as lens flare, haze, and ghosting in images capturedwith the camera because the portion of the light entering through thefront (object side) of a light-absorbing flange lens is absorbed ratherthan being reflected by surfaces of the flange and exiting through theimage side of the lens element as in unibody lens elements. In someembodiments, the refractive index of the optical light-absorbingmaterial used in the flange of the lens element may be higher than therefractive index of the optical transparent material used in theeffective area of the lens element. This may help to further improve thereduction of flare or other aberrations. In addition, the flangecomposed of an optical light-absorbing material may allow the lensbarrel to be reduced or eliminated, thus reducing the diameter of thelens system.

FIG. 9 illustrates a flange of a lens element that is at least partiallycomposed of an optical material that absorbs visible light and transmitsinfrared (IR) light, according to some embodiments. In some embodiments,the flange of a light-absorbing flange lens as described herein may becomposed of an optical material that absorbs light in the visibleportion of the spectrum while transmitting at least a portion of thelight in the IR portion of the spectrum. This may allow mechanicalfeatures of the camera/lens to be detected using IR light, for exampleallowing the lenses to be inspected using IR light during or aftermanufacture.

FIGS. 10, 11A, and 11B illustrate example methods for manufacturinglight-absorbing flange lenses as described herein, according to someembodiments. In some embodiments, a light-absorbing flange lens may becomposed of two different plastic materials, with a transparent plasticmaterial used for the effective area of the lens element and an opticalmaterial that absorbs at least a portion of light used for at least aportion of the flange. In some embodiments, the light-absorbing flangelens may be formed using an injection molding process. As illustrated inFIG. 10 , in some embodiments, the light-absorbing flange lens may beformed using an injection molding process in which the flange is formedfirst, followed by the effective area. However, as illustrated in FIG.11A, in some embodiments, the light-absorbing flange lens may be formedusing an injection molding process in which the effective area is formedfirst, followed by the flange. As illustrated in FIG. 11B, in someembodiments, the light-absorbing flange lens may be formed using aninjection molding process in which the effective (center) area of thelens element and part of the flange are formed of a transparent materialbefore a light-absorbing part of the flange is formed.

Note that, in some embodiments, the entire flange may be formed of theoptical light-absorbing material. However, in some embodiments, aportion but not all of the flange may be formed of the opticallight-absorbing material, for example as illustrated in FIG. 11B.Further note that, in some embodiments of a lens stack, all of the lenselements may be light-absorbing flange lenses as described herein.However, in some embodiments, one or more of the lens elements in thelens stack may be light-absorbing flange lenses as described herein,while one or more others of the lens elements in the lens stack may beunibody lenses.

FIG. 12 is a high-level flowchart of a method for capturing images usinga camera that includes a lens stack in which the flanges of one or moreof the lens elements are at least partially composed of an opticallight-absorbing material as illustrated in FIGS. 4A and 4B, according tosome embodiments. As indicated at 1200, light from an object field infront of the camera is received at a first lens element in the lensstack. The lens stack may include multiple (e.g., three, four, five,etc.) lens elements arranged along an optical axis of the camera fromthe first lens element to a last lens element. FIGS. 6, 7 and 9 shownon-limiting examples of lens stacks that may be used. As indicated at1202, the light is refracted by the lens elements in the lens stack toform an image at an image plane at or near the surface of a photosensorof the camera. A portion of the light that enters the flanges of thelens elements is absorbed by a light-absorbing material of which atleast a portion of the flanges are composed. As indicated at 1204, theimage is captured by the photosensor. While not shown, in someembodiments, the light may pass through an infrared filter that may forexample be located between the last lens element in the lens stack andthe photosensor.

Light-Absorbing Flanges for Other Optical Elements

Embodiments of refractive lenses with light-absorbing flanges foroptical systems have been described. However, an optical system orcamera may include other optical elements, for example one or moreprisms that fold the optical axis of the optical system and/or one ormore filters such as infrared (IR) filters, for example as shown inFIGS. 13A and 13B. FIG. 13A shows an optical system 1300A that includes,in order from an object side to an image side on an optical axis, aprism 1390 that folds the optical axis, a lens stack 1310 that includesone or more refractive lens elements (for example, one or morelight-absorbing flange lenses as illustrated in FIGS. 4 through 9 ), anIR filter 1340 (optional), and a photosensor 1350. Prism 1390 may, butdoes not necessarily, have optical power. FIG. 13B shows an opticalsystem 1300B that includes, in order from an object side to an imageside on an optical axis, a first prism 1390A that folds the opticalaxis, a lens stack 1310 that includes one or more refractive lenselements (for example, one or more light-absorbing flange lenses asillustrated in FIGS. 4 through 9 ), a second prism 1390B that folds theoptical axis, an IR filter 1340 (optional), and a photosensor 1350. Oneor both prisms 1390A and 1390B may, but do not necessarily, have opticalpower.

In conventional optical systems that include an IR filter 1340, the IRfilter 1340 is typically mounted in a barrel with the refractive lensesin the lens stack, for example as shown in FIG. 2A. As shown in FIG.13C, in conventional optical systems that include prism(s) 1390 as shownin FIGS. 13A and 13B, the off-axis sides 1392A and 1392B of the prism1390 are typically coated with a black material, and the prism 1390 ismounted in a relatively thick, rigid holder 1394 that is necessary toprovide mechanical strength.

Various embodiments of prisms that are formed with light-absorbingholders are described that may be used in the lens stack instead ofconventional prisms as shown in FIG. 13C. In these prisms, the effectivearea is composed of a transparent optical material; however, the holderis composed of an optical light-absorbing material that absorbs at leasta portion of the light that enters the holder. The holders may be lessthick than the holders used in conventional optical systems as shown inFIG. 13C, and may thus reduce the total size of the optical system. Thismay have a significant impact on the X-Y size of the camera by reducingthe size of the camera in the X-Y dimensions.

In conventional prisms as shown in FIG. 13C, the off-axis sides 1392Aand 1392B of the prism 1390 may cause total internal reflection (TIR) ofsome light rays that strike the sides, which may result in “TIR flare”in images captured by the camera. In addition to reducing the size ofthe optical system, using a light-absorbing material in the holders ofthe prisms may reduce or eliminate TIR caused by the off-axis sides ofthe prism because the light rays are absorbed by the material of theholder rather than being reflected by the surfaces of the prism.

Similarly, filters such as IR filter 1340 shown in FIGS. 13A and 13B maybe formed with a light-absorbing holder to reduce size of the opticalsystem and/or to reduce or eliminate TIR at the edges of the filter.

In some embodiments, a prism formed with a holder as described hereinmay be composed of two different plastic materials, with a transparentplastic material used for the effective area of the prism and an opticalmaterial that absorbs at least a portion of light used for the holder.In some embodiments, the prism and holder may be formed using aninjection molding process, for example a process similar to thosedescribed in reference to FIGS. 10 through 12 for manufacturinglight-absorbing flange lenses. Similarly, a filter formed with a holderas described herein may be composed of two different plastic materials,with a plastic material with properties that vary based on the purposeof the filter used for the effective area of the filter (e.g., IRfiltering properties for an IR filter) and an optical material thatabsorbs at least a portion of light used for the holder.

Embodiments of prisms and/or filters formed with light-absorbing holdersmay be used in infrared camera applications as well as in visible lightcamera applications. In some embodiments, the light-absorbing materialin the holder is an optical material that absorbs both visible light andinfrared (IR) light. However, in some embodiments, the light-absorbingmaterial is an optical material that absorbs light in the visibleportion of the spectrum while transmitting at least a portion of thelight in the IR portion of the spectrum. This may allow mechanicalfeatures of the optical system to be detected using IR light, forexample allowing the optical system to be inspected using IR lightduring or after manufacture.

Embodiments of a small format factor camera with an optical system thatincludes prisms and/or filters as described herein may be implemented ina small package size while still capturing sharp, high-resolutionimages, making embodiments of the camera suitable for use in smalland/or mobile multipurpose devices such as cell phones, smartphones, pador tablet computing devices, laptop, netbook, notebook, subnotebook, andultrabook computers, and so on. However, note that aspects of theoptical system may be scaled up or down to provide cameras with largeror smaller package sizes. In addition, embodiments of the camera systemmay be implemented as stand-alone digital cameras. In addition to still(single frame capture) camera applications, embodiments of the camerasystem may be adapted for use in video camera applications. In additionto visible light camera applications, embodiments of the prisms andfilters may be used in infrared camera applications. In someembodiments, a camera as described herein may be included in a devicealong with one or more other cameras such as a wider-field small formatcamera or a telephoto or narrow angle small format camera, which wouldfor example allow the user to select between the different cameraformats (e.g., normal, telephoto or wide-field) when capturing imageswith the device. In some embodiments, two or more small format camerasas described herein may be included in a device, for example asfront-facing and rear-facing cameras in a mobile device.

FIG. 14 illustrates an example prism 1400 formed with a light-absorbingholder 1420, according to some embodiments. The effective area 1410 ofthe prism may be composed of a visible and infrared (IR) lighttransparent optical material. The holder 1420 is composed of an opticalmaterial that absorbs light that enters the holder 1420. Light enteringan object side of the prism 1400 is redirected by a reflective side 1412of the prism, thus folding the optical axis, and exits at an image sideof the prism 1400. Using a light-absorbing material for the holder 1420may reduce or eliminate optical aberrations such as flare caused by TIRof light at the off-axis sides of the prism 1400. In addition, theholder 1420 may be less thick than conventional holders for prisms asillustrated in FIG. 13C.

FIG. 15 illustrates an example prism 1500 with optical power formed witha light-absorbing holder 1520, according to some embodiments. In theexample prism 1400 of FIG. 14 , the object side, reflective side 1412,and image side of the effective area 1410 are flat surfaces. In theexample prism 1500 of FIG. 15 , one or more of the object side,reflective side 1512, and image side of the prism 1500 may be curvedsurfaces (spherical, aspherical, convex, concave, etc.) so that theprism 1500 has positive or negative refractive power. The effective area1510 of the prism may be composed of a visible and infrared (IR) lighttransparent optical material. The holder 1520 is composed of an opticalmaterial that absorbs light that enters the holder 1520. Light enteringan object side of the prism 1500 is redirected by a reflective side 1512of the prism, thus folding the optical axis, and exits at an image sideof the prism 1500. Using a light-absorbing material for the holder 1520may reduce or eliminate optical aberrations such as flare caused by TIRof light at the off-axis sides of the prism 1500. In addition, theholder 1520 may be less thick than conventional holders for prisms asillustrated in FIG. 13C.

FIG. 16 illustrates an example prism 1600 with optical power formed witha light-absorbing holder 1620 that includes a mounting structure 1622,according to some embodiments. The effective area 1610 of the prism maybe similar to that of the prisms 1400 and 1500 shown in FIGS. 14 and 15. However, the holder 1620 is formed with a mounting structure 1622 onthe sides to facilitate mounting of the prism 1600 in an opticalsystem/camera. The effective area 1610 of the prism may be composed of avisible and infrared (IR) light transparent optical material. The holder1620 is composed of an optical material that absorbs light that entersthe holder 1620. Light entering an object side of the prism 1600 isredirected by a reflective side 1612 of the prism, thus folding theoptical axis, and exits at an image side of the prism 1600. Using alight-absorbing material for the holder 1620 may reduce or eliminateoptical aberrations such as flare caused by TIR of light at the off-axissides of the prism 1600. In addition, the holder 1620 may be less thickthan conventional holders for prisms as illustrated in FIG. 13C.

FIG. 17 illustrates an example prism 1700 formed with an alternativelight-absorbing holder 1720, according to some embodiments. Theeffective area 1710 of the prism may be similar to that of the prisms1400 and 1500 shown in FIGS. 14 and 15 . However, the holder 1720 ismore similar to a bracket, and does not cover the entire off-axis sidesof the effective area 1710 of the prism. The effective area 1710 of theprism may be composed of a visible and infrared (IR) light transparentoptical material. The holder 1720 is composed of an optical materialthat absorbs light that enters the holder 1720. Light entering an objectside of the prism 1700 is redirected by a reflective side 1712 of theprism, thus folding the optical axis, and exits at an image side of theprism 1700. Using a light-absorbing material for the holder 1720 mayhelp to reduce optical aberrations such as flare caused by TIR of lightat the off-axis sides of the prism 1700. In addition, the holder 1520may be smaller than conventional holders for prisms as illustrated inFIG. 13C.

FIG. 18 illustrates an example infrared (IR) filter 1800 formed with alight-absorbing holder 1820, according to some embodiments. Theeffective area 1810 of the filter may be composed of a visible lighttransparent and IR light absorbing optical material. The holder 1820 iscomposed of an optical material that absorbs light that enters theholder 1820. Using a light-absorbing material for the holder 1820 mayreduce or eliminate optical aberrations such as flare caused by TIR oflight at the sides of the filter 1800. In addition, the holder 1820 maybe smaller than conventional holders for filters in optical systems.

While embodiments of lenses, prisms, and filters that are formed withlight-absorbing flanges or holders are described herein, similar methodsmay be used to form other optical elements with light-absorbing flangesor holders.

Example Computing Device

FIG. 19 illustrates an example computing device, referred to as computersystem 2000, that may include or host embodiments of the camera asillustrated in FIGS. 1 through 12 . In addition, computer system 2000may implement methods for controlling operations of the camera and/orfor performing image processing of images captured with the camera. Indifferent embodiments, computer system 2000 may be any of various typesof devices, including, but not limited to, a personal computer system,desktop computer, laptop, notebook, tablet or pad device, slate, ornetbook computer, mainframe computer system, handheld computer,workstation, network computer, a camera, a set top box, a mobile device,a wireless phone, a smartphone, a consumer device, video game console,handheld video game device, application server, storage device, atelevision, a video recording device, a peripheral device such as aswitch, modem, router, or in general any type of computing or electronicdevice.

In the illustrated embodiment, computer system 2000 includes one or moreprocessors 2010 coupled to a system memory 2020 via an input/output(I/O) interface 2030. Computer system 2000 further includes a networkinterface 2040 coupled to I/O interface 2030, and one or moreinput/output devices 2050, such as cursor control device 2060, keyboard2070, and display(s) 2080. Computer system 2000 may also include one ormore cameras 2090, for example one or more cameras as described abovewith respect to FIGS. 1 through 19 , which may also be coupled to I/Ointerface 2030, or one or more cameras as described above with respectto FIGS. 1 through 18 along with one or more other cameras such aswide-field and/or telephoto cameras.

In various embodiments, computer system 2000 may be a uniprocessorsystem including one processor 2010, or a multiprocessor systemincluding several processors 2010 (e.g., two, four, eight, or anothersuitable number). Processors 2010 may be any suitable processor capableof executing instructions. For example, in various embodimentsprocessors 2010 may be general-purpose or embedded processorsimplementing any of a variety of instruction set architectures (ISAs),such as the x86, PowerPC, SPARC, or MIPS ISAs, or any other suitableISA. In multiprocessor systems, each of processors 2010 may commonly,but not necessarily, implement the same ISA.

System memory 2020 may be configured to store program instructions 2022and/or data 2032 accessible by processor 2010. In various embodiments,system memory 2020 may be implemented using any suitable memorytechnology, such as static random access memory (SRAM), synchronousdynamic RAM (SDRAM), nonvolatile/Flash-type memory, or any other type ofmemory. In the illustrated embodiment, program instructions 2022 may beconfigured to implement various interfaces, methods and/or data forcontrolling operations of camera 2090 and for capturing and processingimages with integrated camera 2090 or other methods or data, for exampleinterfaces and methods for capturing, displaying, processing, andstoring images captured with camera 2090. In some embodiments, programinstructions and/or data may be received, sent or stored upon differenttypes of computer-accessible media or on similar media separate fromsystem memory 2020 or computer system 2000.

In one embodiment, I/O interface 2030 may be configured to coordinateI/O traffic between processor 2010, system memory 2020, and anyperipheral devices in the device, including network interface 2040 orother peripheral interfaces, such as input/output devices 2050. In someembodiments, I/O interface 2030 may perform any necessary protocol,timing or other data transformations to convert data signals from onecomponent (e.g., system memory 2020) into a format suitable for use byanother component (e.g., processor 2010). In some embodiments, I/Ointerface 2030 may include support for devices attached through varioustypes of peripheral buses, such as a variant of the Peripheral ComponentInterconnect (PCI) bus standard or the Universal Serial Bus (USB)standard, for example. In some embodiments, the function of I/Ointerface 2030 may be split into two or more separate components, suchas a north bridge and a south bridge, for example. Also, in someembodiments some or all of the functionality of I/O interface 2030, suchas an interface to system memory 2020, may be incorporated directly intoprocessor 2010.

Network interface 2040 may be configured to allow data to be exchangedbetween computer system 2000 and other devices attached to a network2085 (e.g., carrier or agent devices) or between nodes of computersystem 2000. Network 2085 may in various embodiments include one or morenetworks including but not limited to Local Area Networks (LANs) (e.g.,an Ethernet or corporate network), Wide Area Networks (WANs) (e.g., theInternet), wireless data networks, some other electronic data network,or some combination thereof. In various embodiments, network interface2040 may support communication via wired or wireless general datanetworks, such as any suitable type of Ethernet network, for example;via telecommunications/telephony networks such as analog voice networksor digital fiber communications networks; via storage area networks suchas Fibre Channel SANs, or via any other suitable type of network and/orprotocol.

Input/output devices 2050 may, in some embodiments, include one or moredisplay terminals, keyboards, keypads, touchpads, scanning devices,voice or optical recognition devices, or any other devices suitable forentering or accessing data by computer system 2000. Multipleinput/output devices 2050 may be present in computer system 2000 or maybe distributed on various nodes of computer system 2000. In someembodiments, similar input/output devices may be separate from computersystem 2000 and may interact with one or more nodes of computer system2000 through a wired or wireless connection, such as over networkinterface 2040.

As shown in FIG. 19 , memory 2020 may include program instructions 2022,which may be processor-executable to implement any element or action tosupport integrated camera 2090, including but not limited to imageprocessing software and interface software for controlling camera 2090.In some embodiments, images captured by camera 2090 may be stored tomemory 2020. In addition, metadata for images captured by camera 2090may be stored to memory 2020.

Those skilled in the art will appreciate that computer system 2000 ismerely illustrative and is not intended to limit the scope ofembodiments. In particular, the computer system and devices may includeany combination of hardware or software that can perform the indicatedfunctions, including computers, network devices, Internet appliances,PDAs, wireless phones, pagers, video or still cameras, etc. Computersystem 2000 may also be connected to other devices that are notillustrated, or instead may operate as a stand-alone system. Inaddition, the functionality provided by the illustrated components mayin some embodiments be combined in fewer components or distributed inadditional components. Similarly, in some embodiments, the functionalityof some of the illustrated components may not be provided and/or otheradditional functionality may be available.

Those skilled in the art will also appreciate that, while various itemsare illustrated as being stored in memory or on storage while beingused, these items or portions of them may be transferred between memoryand other storage devices for purposes of memory management and dataintegrity. Alternatively, in other embodiments some or all of thesoftware components may execute in memory on another device andcommunicate with the illustrated computer system 2000 via inter-computercommunication. Some or all of the system components or data structuresmay also be stored (e.g., as instructions or structured data) on acomputer-accessible medium or a portable article to be read by anappropriate drive, various examples of which are described above. Insome embodiments, instructions stored on a computer-accessible mediumseparate from computer system 2000 may be transmitted to computer system2000 via transmission media or signals such as electrical,electromagnetic, or digital signals, conveyed via a communication mediumsuch as a network and/or a wireless link. Various embodiments mayfurther include receiving, sending or storing instructions and/or dataimplemented in accordance with the foregoing description upon acomputer-accessible medium. Generally speaking, a computer-accessiblemedium may include a non-transitory, computer-readable storage medium ormemory medium such as magnetic or optical media, e.g., disk orDVD/CD-ROM, volatile or non-volatile media such as RAM (e.g. SDRAM, DDR,RDRAM, SRAM, etc.), ROM, etc. In some embodiments, a computer-accessiblemedium may include transmission media or signals such as electrical,electromagnetic, or digital signals, conveyed via a communication mediumsuch as network and/or a wireless link.

The methods described herein may be implemented in software, hardware,or a combination thereof, in different embodiments. In addition, theorder of the blocks of the methods may be changed, and various elementsmay be added, reordered, combined, omitted, modified, etc. Variousmodifications and changes may be made as would be obvious to a personskilled in the art having the benefit of this disclosure. The variousembodiments described herein are meant to be illustrative and notlimiting. Many variations, modifications, additions, and improvementsare possible. Accordingly, plural instances may be provided forcomponents described herein as a single instance. Boundaries betweenvarious components, operations and data stores are somewhat arbitrary,and particular operations are illustrated in the context of specificillustrative configurations. Other allocations of functionality areenvisioned and may fall within the scope of claims that follow. Finally,structures and functionality presented as discrete components in theexample configurations may be implemented as a combined structure orcomponent. These and other variations, modifications, additions, andimprovements may fall within the scope of embodiments as defined in theclaims that follow.

1.-22. (canceled)
 23. An optical element, comprising: an effective areacomposed of a transparent optical material that is configured to receivelight at an incoming surface of the optical element and transmit thereceived light toward an exiting surface of the optical element; and aflange around the effective area, wherein at least a portion of theflange is composed of an optical light-absorbing material that is indirect contact with at least a portion of a lateral boundary of theeffective area, wherein the direct contact is along an entirety of athickness of the optical element, the thickness extending along anoptical axis from the incoming surface to the exiting surface, whereinthe optical light-absorbing material absorbs at least a portion of lightthat enters the flange.
 24. The optical element as recited in claim 23,wherein the optical light-absorbing material absorbs light in a visibleportion of the spectrum while transmitting at least a portion of lightin an infrared portion of the spectrum.
 25. The optical element asrecited in claim 23, wherein the optical light-absorbing materialabsorbs light in a visible portion of the spectrum and light in aninfrared portion of the spectrum.
 26. The optical element as recited inclaim 23, wherein a refractive index of the optical light-absorbingmaterial is higher than a refractive index of the transparent opticalmaterial.
 27. The optical element as recited in claim 23, wherein thetransparent optical material and the optical light-absorbing materialare optical plastic materials.
 28. The optical element as recited inclaim 23, wherein the effective area is an optical prism.
 29. Theoptical element as recited in claim 23, wherein the effective area is anoptical filter.
 30. A camera, comprising: a photosensor configured tocapture light projected onto a surface of the photosensor; and anoptical element configured to transmit light from an object fieldlocated in front of the camera toward the surface of the photosensor,wherein the optical element comprises: an effective area composed of atransparent optical material that is configured to receive light at anincoming surface of the optical element and transmit the received lighttoward the photosensor via an exiting surface of the optical element;and a flange at least partially surrounding the effective area, whereinat least a portion of the flange is composed of an opticallight-absorbing material that is in direct contact with at least aportion of a lateral boundary of the effective area, wherein the directcontact is along an entirety of a thickness of the optical element, thethickness extending from the incoming surface to the exiting surfacealong the optical axis, wherein the optical light-absorbing materialabsorbs at least a portion of light that enters the flange.
 31. Thecamera as recited in claim 30, wherein the optical light-absorbingmaterial is configured to absorb light in a visible portion of thespectrum while transmitting at least a portion of light in an infraredportion of the spectrum.
 32. The camera as recited in claim 30, whereinthe optical light-absorbing material is configured to absorb light in avisible portion of the spectrum and light in an infrared portion of thespectrum.
 33. The camera as recited in claim 30, wherein a refractiveindex of the optical light-absorbing material is higher than arefractive index of the transparent optical material.
 34. The camera asrecited in claim 30, wherein the transparent optical material and theoptical light-absorbing material are optical plastic materials.
 35. Thecamera as recited in claim 30, wherein the transparent optical materialand the optical light-absorbing material are composed of glassmaterials.
 36. The camera as recited in claim 30, wherein the opticalelement has refractive power to refract the received light toward animage plane at or near the surface of the photosensor.
 37. The camera asrecited in claim 30, further comprising at least one aperture stop. 38.The camera as recited in claim 30, wherein the effective area is anoptical prism.
 39. The camera as recited in claim 38, wherein theeffective area is an optical filter.
 40. A method, comprising:receiving, by an optical element of a camera, light from an object fieldof a camera comprising the optical element and a photosensor, whereinthe optical element comprises: an effective area composed of atransparent optical material that is configured to receive light at anincoming surface of the optical element and transmit the received lighttoward an exiting surface of the optical element; and a flange at leastpartially surrounding the effective area, wherein at least a portion ofthe flange is composed of an optical light-absorbing material that is indirect contact with at least a portion of a lateral boundary of theeffective area, wherein the direct contact is along an entirety of athickness of the optical element, the thickness extending from theincoming surface to the exiting surface along the optical axis;absorbing, by the flange, at least a portion of the received light thatenters the flange; and transmitting, by the effective area, at least aportion of the received light that has entered the effective area fromthe exiting surface toward a surface of the photosensor.
 41. The methodof claim 40, further comprising refracting, by the effective area, thelight that has entered the effective area, wherein the light that hasbeen refracted forms an image at an image plane at or near the surfaceof the photosensor.
 42. The method of claim 39, further comprisingfiltering, by an infrared filter, the light transmitted from theeffective area toward the surface of the photosensor.